Remove magic number for Mac focus ring alpha

Prior to this CL, there was a magic 166 alpha applied to the
system focus ring color (the Accent Color setting). This has
now been pulled into native_theme.

Along the way, I also added a Color::operator SkColor() to
convert blink::Color to SkColor, and used it in gradient.cc,
along with here in layout_theme_mac.mm. I'm sure there are
other such converters sprinkled around which could be
migrated, but this was all I found.

Quick note on testing: this change will be best tested by [1]
once it lands.

[1] https://chromium-review.googlesource.com/c/chromium/src/+/2150765

Fixed: 1108169
Change-Id: I54ac4e60a1df1b39123721adffda9f39aac94fe4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2317294
Auto-Submit: Mason Freed <masonfreed@chromium.org>
Reviewed-by: Elly Fong-Jones <ellyjones@chromium.org>
Reviewed-by: Kent Tamura <tkent@chromium.org>
Commit-Queue: Mason Freed <masonfreed@chromium.org>
Cr-Commit-Position: refs/heads/master@{#792223}

chrome/browser/ui/views/accessibility/accessibility_focus_highlight.cc

@@ -133,7 +133,8 @@ SkColor AccessibilityFocusHighlight::GetHighlightColor() {
   if (theme_color == SK_ColorTRANSPARENT || use_default_color_for_testing_)
     return default_color_;
 
-  return theme_color;
+  return browser_view_->GetNativeTheme()->FocusRingColorForBaseColor(
+      theme_color);
 }
 
 void AccessibilityFocusHighlight::CreateOrUpdateLayer(gfx::Rect node_bounds) {
@@ -256,10 +257,6 @@ void AccessibilityFocusHighlight::OnPaintLayer(
     const ui::PaintContext& context) {
   ui::PaintRecorder recorder(context, layer_->size());
   SkColor highlight_color = GetHighlightColor();
-#if defined(OS_MACOSX)
-  // Match blink::LayoutThemeMacRefresh::FocusRingColor()
-  highlight_color = SkColorSetA(highlight_color, 166);
-#endif
 
   cc::PaintFlags original_flags;
   original_flags.setAntiAlias(true);

third_party/blink/renderer/core/layout/layout_theme_mac.mm

@@ -362,13 +362,12 @@ Color LayoutThemeMacRefresh::FocusRingColor() const {
   // TODO(crbug.com/929098) Need to pass an appropriate color scheme here.
   WebColorScheme color_scheme = ComputedStyle::InitialStyle().UsedColorScheme();
 
-  Color keyboard_focus_indicator =
-      GetSystemColor(MacSystemColorID::kKeyboardFocusIndicator, color_scheme);
-  // Take the RGB values from the keyboard_focus_indicator color, but use a
-  // different alpha value to avoid having a color too light.
+  SkColor keyboard_focus_indicator = SkColor(
+      GetSystemColor(MacSystemColorID::kKeyboardFocusIndicator, color_scheme));
   Color focus_ring =
-      Color(keyboard_focus_indicator.Red(), keyboard_focus_indicator.Green(),
-            keyboard_focus_indicator.Blue(), /*alpha=*/166);
+      ui::NativeTheme::GetInstanceForWeb()->FocusRingColorForBaseColor(
+          keyboard_focus_indicator);
+
   if (!HasCustomFocusRingColor())
     return focus_ring;
   // Use the custom focus ring color when the system accent color wasn't

third_party/blink/renderer/platform/graphics/color.cc

@@ -33,6 +33,7 @@
 #include "third_party/blink/renderer/platform/wtf/math_extras.h"
 #include "third_party/blink/renderer/platform/wtf/text/string_builder.h"
 #include "third_party/blink/renderer/platform/wtf/text/string_view.h"
+#include "third_party/skia/include/core/SkColor.h"
 
 namespace blink {
 
@@ -261,6 +262,10 @@ bool Color::SetNamedColor(const String& name) {
   return found_color;
 }
 
+Color::operator SkColor() const {
+  return SkColorSetARGB(Alpha(), Red(), Green(), Blue());
+}
+
 Color Color::Light() const {
   // Hardcode this common case for speed.
   if (color_ == kBlack)

third_party/blink/renderer/platform/graphics/color.h

@@ -31,6 +31,8 @@
 #include "third_party/blink/renderer/platform/wtf/forward.h"
 #include "third_party/blink/renderer/platform/wtf/text/unicode.h"
 
+typedef uint32_t SkColor;
+
 namespace blink {
 
 class Color;
@@ -120,6 +122,8 @@ class PLATFORM_EXPORT Color {
   void GetRGBA(double& r, double& g, double& b, double& a) const;
   void GetHSL(double& h, double& s, double& l) const;
 
+  explicit operator SkColor() const;
+
   Color Light() const;
   Color Dark() const;
 

third_party/blink/renderer/platform/graphics/gradient.cc

@@ -85,11 +85,6 @@ void Gradient::SortStopsIfNecessary() {
   std::stable_sort(stops_.begin(), stops_.end(), CompareStops);
 }
 
-// FIXME: This would be more at home as Color::operator SkColor.
-static inline SkColor MakeSkColor(const Color& c) {
-  return SkColorSetARGB(c.Alpha(), c.Red(), c.Green(), c.Blue());
-}
-
 // Collect sorted stop position and color information into the pos and colors
 // buffers, ensuring stops at both 0.0 and 1.0.
 // TODO(fmalita): theoretically Skia should provide the same 0.0/1.0 padding
@@ -108,18 +103,18 @@ void Gradient::FillSkiaStops(ColorBuffer& colors, OffsetBuffer& pos) const {
     pos.push_back(WebCoreDoubleToSkScalar(0));
     if (color_filter_) {
       colors.push_back(
-          color_filter_->filterColor(MakeSkColor(stops_.front().color)));
+          color_filter_->filterColor(SkColor(stops_.front().color)));
     } else {
-      colors.push_back(MakeSkColor(stops_.front().color));
+      colors.push_back(SkColor(stops_.front().color));
     }
   }
 
   for (const auto& stop : stops_) {
     pos.push_back(WebCoreDoubleToSkScalar(stop.stop));
     if (color_filter_)
-      colors.push_back(color_filter_->filterColor(MakeSkColor(stop.color)));
+      colors.push_back(color_filter_->filterColor(SkColor(stop.color)));
     else
-      colors.push_back(MakeSkColor(stop.color));
+      colors.push_back(SkColor(stop.color));
   }
 
   // Copy the last stop to 1.0 if needed. See comment above about this float

ui/native_theme/native_theme.cc

@@ -203,6 +203,10 @@ SkColor NativeTheme::GetSystemButtonPressedColor(SkColor base_color) const {
   return base_color;
 }
 
+SkColor NativeTheme::FocusRingColorForBaseColor(SkColor base_color) const {
+  return base_color;
+}
+
 float NativeTheme::GetBorderRadiusForPart(Part part,
                                           float width,
                                           float height,

ui/native_theme/native_theme.h

@@ -471,6 +471,9 @@ class NATIVE_THEME_EXPORT NativeTheme {
   // pressed states.
   virtual SkColor GetSystemButtonPressedColor(SkColor base_color) const;
 
+  // Assign the focus-ring-appropriate alpha value to the provided base_color.
+  virtual SkColor FocusRingColorForBaseColor(SkColor base_color) const;
+
  protected:
   explicit NativeTheme(bool should_only_use_dark_colors);
   virtual ~NativeTheme();

ui/native_theme/native_theme_aura.cc

@@ -100,6 +100,17 @@ NativeThemeAura* NativeThemeAura::web_instance() {
   return s_native_theme_for_web.get();
 }
 
+SkColor NativeThemeAura::FocusRingColorForBaseColor(SkColor base_color) const {
+#if defined(OS_MACOSX)
+  DCHECK(features::IsFormControlsRefreshEnabled());
+  // On Mac OSX, the system Accent Color setting is darkened a bit
+  // for better contrast.
+  return SkColorSetA(base_color, 166);
+#else
+  return base_color;
+#endif  // OS_MACOSX
+}
+
 void NativeThemeAura::PaintMenuPopupBackground(
     cc::PaintCanvas* canvas,
     const gfx::Size& size,

ui/native_theme/native_theme_aura.h

@@ -24,6 +24,9 @@ class NATIVE_THEME_EXPORT NativeThemeAura : public NativeThemeBase {
 
   static NativeThemeAura* web_instance();
 
+  // Overridden from NativeTheme:
+  SkColor FocusRingColorForBaseColor(SkColor base_color) const override;
+
   // NativeThemeBase:
   void PaintMenuPopupBackground(
       cc::PaintCanvas* canvas,